Lathes



J 31, 1967 R. J. N. LE BRUSQUE 3,30fl,06

LATHES 7 Sheets-Sheet 1 Filed Sept. 11, 1964 Jan. 3, 1967 R. J. N. LEBRUSQU 3,3,W

LATHES T Sheets-Sheet 2 Filed Sept. 11, 1964 Jan. 3L 1967 R. J. N. LEBRUSQUE LATHES 7 SheetsSheet 5 Filed Sept. 11, 1964 Jan. 31, 1967 R. J.N. LE BRUSQUE 3,301,106'

LATHES Filed Sept. 11, 1964 7 Sheets-Sheet 5 Jan. 31, 1967 J, LE BRUSQUE3,301,106

LATHES 7 Sheecs-Sheet 6 Filed Sept. 11, 1964 uaan. (H, 1967 J, LEBRUSQUE 3,301,106

LATHES 7 Sheets-Sheet 7 Filed Sept. 11, 1964 FIG.

United States Patent Filed Sept. 11. 1964-, Sel. No. 395,695 Claimspriority, application France, Sept. 25, 1963,

8 Claims. CL 8221) The invention relates to lathes having a tool-holdingcapstan assemhled so as to be able to be subjected to a revolving motionabout an axis parallel to the lathe spindle and a motion of translationin a direction parallel to said axis.

With regard to the revolving motion, it is necessary on the one hand tobe able to make the capstan turn about its axis in order to occupy thediflerent angular indexing positions for which the tools carried by itsfaces successively present themselves at the working station and, on theother hand, it is advantageous to have said capstan carry out anoscillating or angularly balancing motion having for its origin each ofsaid angular indexing positions so as to conter to the tools atransverse motion, e.g. for a shoulder surfacing operation.

Moreover, to ensure the precision of the operation as well as thesurface quality and finish the angular position of the capstan and, moreparticularly, each of its indexing positions must at any time bedetermined with precision, i.e. by elements which are not subjected tothe effects of various clearances.

In lathes of the type considered each of the indexing positions of thecapstan is determined by a reference member which assumes only thisparticular function, and the angular balancing motion of the capstan isdetermined by a mechanism which is independent from said referencemember. This has for affect that at the moment when the capstan stopsbeing blocked hy said referen member to be taken over by the angularbalancing mechanism, and vice-versa, it is possible and even likely thatsome of the play is taken up, which is prejudicial both to the precisionand the quality of the work and may lead to a tool breakage. Indeed,when the angular balancing motion et the capstan is initiated the toolis generally carrying ont its operation and, consequently, engaged Withthe work-piece, so that the reaction to which it subjects the capstan-yresting on the workpieceis liable to cause the play to be taken up atthat very moment. Furthermore, the amplitude et the angular balancingmotion, i.e. the location of its point of departure and its point ofarrival, with respect to the indexing position does not always presentthe desired precision.

It is the object of the invention to realize a capstan lathe of the typeconsidered which overcomes this drawback.

To this effect, in a lathe according to the invention the menber whichmaintains the capstan in each of its angular indexing positions ismovable on the lathe fram-e between a stationary stop block whichdetermines said position and an extreme position which determines theposition of maximum amplitude of the angular balancing motion of thecapstan which is caused by the displacement of said maintaining memberwhich permanently determines the angnlar position of the capstan underthe eifect et convenient control means.

Thus, from the moment when the capstan initiates an operating cycle, andwhichever the succession of its motion of translation in one or theother direction and its pivoting movements in one direction or theother, it never ceases to be under the control of said singlemaintaining member which ensures maintenance of the angular positionthereof. This condition is particularly favorable Patented Jan. 31, 1967for obtaining a high precision workpiece. Moreover, a structure of thiskind easily suflamits to a control of its movements when running.

In one embodiment of the invention, the member which permanentlydoter-mines the angular position of the capstan is constituted by aprismatic guide adapted to engage With any one of a series of radialgrooves provided at the periphery of a plate which is integral with thecapstan, said guide being connected to a movable slide table in anorthogonal direction with respect to the capstan axis, and subjected tothe eIect of the aforementioned control means.

Thus, it is this guide which during the whole of the duration of acapstan operating cycle maintains the latter in its an-gular referenceindexing position and confers the angular balancing motion thereto. Itoiers the advantage of allowing to determine with great precision thedistance between the tool and the work-piece during the machiningoperations since it is possible to provide the same With a relativelygreat diameter and, more particularly, with a diameter greater than thediameter within whose limits the tools perform their revolving motions,so that a displacement of the slide table causes the capstan to performan angular movement which displas the centreof the tool over a muchshorter distance.

Furthermore, in the case of a longitudinal machining operation such astunning along or =boring by means of a sole tool, it has been customaryhitherto in capstans With an angular balancing motion to utilize thismovement to carry the tool to its precise adjusting position rather thandisplace the tool on its support, or displace the tool support on thecapstan. To this eifect mechancal end stops or electrical contacts havebeen used to obtain the desired position. The purely mechanical stopsnecessitate the display of relatively considerable forces and thereforedo not lead to a very high precision, and electrical contacts procure byfar not all of the desirable precision either.

This drawback can be overcome by another characteristic feature of theinvention according to which the slide table carrying the guide Whichmaintains the anguiar position of the capstan is connected to one of themembers of a hydraulic jack which is stopped as soon as it isequilibrated under the control of a hydraulic slide-valve controlled bya micrometric stop which is actuated by said slide table.

Hence, only an insignificant effort is required from thismicrometriestcp to place the slide-valve in the position whichcorresponds to the balancing of the jack, so that an extraordinaryprecision can be obtained. In addition, it is possible to adjust thisposition, even during operation of the lathe.

A better understanding of the invention is to be gained from thedescription hereafter as well as from the accompanying drawin'gs whichshow, by way of example, one embodiment of a lathe according to theinvention, and wherein:

FIG. 1 is a perspective view of a capstanlathe according to theinvention, all -of the characteristic elements of the inventionbeing,shownin thick lines, and the capstan heing shown at an intermediary point ofiits axial stroke.

FIG. 2 is a sectional view according to line IIII of FIG. 1, takenthrough a perpendicular plane with respect to the axis of the capstan.

FIG. 3 is a view along IIIIII of FIG. 2.

FIG. 3a is similar to FIG. 3 and show the elements in a difierentposition.

FIG. 4 is a sectional view taken along IVIV of FIG. 2, the capstan beingsupposed to have been brought back to the-end of its axial stroke whichis at the greatest distance from the fast'head stock.

FIG. 5 is a view along VV of FIG. 4.

FIG. 6 is a sectional eut of the control box for the longitudinaladvance movements of the capstan on its axis, through a vertical planparallel to the axis of the capstan.

FIG. 7 is a sectional eut along VI-IVII of FIG. 4.

FIG. 8 is a eut along VIIIVIII of FIG. 4.

FIG. 9 is a view according to IXIX, FIG. 4.

FIG. 10 which is constituted by FIGS. 101 and 10-2 overlying each otheralong lime XX is the electrical connecting diagram of the lathe, and

FIG. 11 is the image of an automatic machining cycle chosen by way ofexample.

The lathe shown in FIG. 1 comprises a head-stock 1 the spindle 2 ofwhich can carry the clamping for the work-piece to be machined, e.g. achuck.

The lathe comprises in addition a prismatic cutter-block capstan which,in this example, has five faces and is assembled so as to be able toturn and slide on a shaft 5 the axis of which is parallel to that oflathe spindle 2.

Capstan 4 carries a plate 6 at the periphery of which are providedgrooves 7 the number of which is equal to that of the capstan faces andthe sides 8 (FIG. 2) of which are parallel in this embodiment.

A stop block 9 (FIG. 2) is used as precision indexing stop for theangular position of capstan 4. This indexing position is obtained bymeans of a slide-table 10 which is displaceable in a stationary zone laintegral with the frame of the lathe and which carries a small plate 11which engages with indexing stop 9. On slide-table 10 is fixed, by meansof screws 12a, an axis 12 which is parallel to the axis of. the capstanand on which a guide constituted by a prism 13 can oscillatc without anynoticeable clearan.

The width of prism 13 is such that the latter can be housed exactlybetween the faces 8 of any one of grooves 7, with a minimum clearance.Thus capstan 4 can move longitudinally on its axis with respect to prism13 whose longitudinal position is stationary. Prism 13 does not extendover the whole length of the axial stroke of plate 6, so that whencapstan 4 has reached the end of its axial stroke the farthest away fromheadstock 1 of the lathe, plate 6 is freed from prism 13, and thecapstan can be turned about its shaft 5.

Slide 10 is controlled by a piston 14 the rod 15 ofwhich is connected tosaid slide by a.small plate 16.

Piston 14 is housed within the cylinder of a hydraulic jack 17 which itdivides. in two chambers 18 and 19.

When the hydraulic jack 17 is operating, slide lmoves carrying alongprism 13, thus determinating an angular movement of capstan 4 about itsshaft 5.

The angular position of capstan 4 is always perfectly precise, from itsindexing position ensured by stop 9 to any predetermined positionobtained by a rotation caused by a displacement of slide 10. Prism 13remains always engaged in a groove 7 of the capstan during oneoscillation of the latter, either to move away from the indexingposition, or to corne back thereto.

The successive angular positions which capstan 4 must occupy on itsshaft can be determined in an extremely precise and entirely automaticway by a hydraulic device comprising stops. which can be adjusted withprecision.

This device comprises a bar 20 retable about its axis and carrying asupport 21 which receives various stops 22 with adjustable positions.When rotating, stop bar 20 can carry one of stops 22 to the path of anextension of plate 16 which is integral with the slide.

Each stop 22 is placed into. its active position by a star 23 which isintegral with. bar 20 and located on the path of two stubs 24, 24acarried by a plate 25a integral with rod 25 of a piston 26 which ismovable in a hydraulic cylinder 27. The jack onstitted by a cylinder 27and piston 26 is fed through hydraulic conduits c and d. At each forwardand return movement of piston 26, the stop bar 20 rotates about aco'rivenient angle t0 substitute one stop 22 for another one. Asupplementary stub 24b which is also carried by a plate 25a blocks star23 in the position shown in FIGS. 2 and 3.

Electric limit switches 28 and 29 are used for checking that piston 26has reached one of the two limit positions which it must occupy toensure the correct successive positioning of stops 22.

An electric limit switch 30 which is placed before the extension ofplate 16 integral with slide 10 serves for controlling that slide 10 hascorne back to the indexing position against stop 9.

Stop bar 20 is mounted in such a way that it can be subjected to slightlongitudinal displacements. During these displacements, it acts uponslide 31 of a valve 32 by means of a lever 33 which rotates about anaxis 34. Bar 20 acts on lever 33 through a stub 35.

FIG. 2 shows valve 32 in the position where slide 10 engages stop 9. Anelectromagnet 36 comprises a movable armature 37 which is normallypushed upwardly by spring 38 and the rod 39 of which is adapted to pushslide 31 downwardly when the electro-magnet is energized. In this case,armature 37 is attracted and compresses spring 38 whereas slide 31 ispushed back downwardly and frees an orifice 40 which connects chamber 18of hydraulic jack 17 to the oil tank. Chamber 19 being always fed withoil under pressure, piston 14 descends and causes the capstan to pivotin the direction indicated by arrow f1 The pivoting speed of the capstancan be adjusted by a freely adjustable throttle 41, which is located onthe connecting duct 136.

When plate 16 has come to engage stop 22, it determines a slightdownward movement of stop bar 20 and, consequently, the upward movementof slide 31 so that orifice 40 is partially obturated thus determiningthe equilibrium of the forces which act upon both sides of piston 14 inthe hydraulic jack 17. The jack is stopped at a point of hydraulicequilibrium in a position which, consequently, may be determined withthe greatest precis1on.

The device is completed by an electric contact 42 which is engaged bythe end 43 of stop bar 20 just before said stop bar starts acting uponslide 31. This contact 42 is time-delayed so as to determine control ofthe ensuing operations with a short delay, i.e., when the point ofhydraulic equilibrium has actually been reached by means of valve 32.

FIGS. 4 and 5 are concerned with the longitudinal displacement ofcapstan 4. It is indeed necessary, not only when operating, to displacethe tool-carrying capstan but also to permit grooves 7 being disengagedfrom prism 13 When it is desired to cause the capstan to pivot to placeother tools in operating position.

T0 disengage a groove 7 from prism 13 it is necessary to carry capstan 4to a Withdrawing position which is shown in FIG. 4.

The longitudinal displacements of the capstan are controlled by ahydraulic jack the cylinder of which is constituted by the inside of thecapstan itself and the piston 44 of which is integral with shaft 5.Piston 44 divides the cylinder into two chambers 45 and 46 fed byhydraulic conduits a and b, respectively.

Plate 6 carries as many rolls 47 (FIGS. 4 and 7) as capstan 4 has faces.These rolls 47 are used for controlling the rotation of the capstan whenit is desired to pass from one face to another one. They are driven bya. fork 48 mounted on an axis 49 the rotation of which is controlled bya hydraulic jack 50 (FIG. 8). This hydraulic jack comprises a piston 51integral with an axis 52, which ends in a fork 53 the prongs .of whichengage with an axis 54 with flattened ends which is carried by a lever55 integral with axis 49.

Chambers 56 and 57 of the hydraulic jack are fed through conduits c andd by means of a hydraulic distributor constituted by an electro-valve58.

When jack 50 is actuated, fork 48 rotates in the direction et atrow J" 2and drives capstan 4 in the direction o arrow il, provided fork 48 isengaged vith a roller 47.

To cause fork 48 to engage With roller 47 it is necessary to provoke alongitudinal displacement of axis 49 of the fork. This displacement isobtained through a jack 59 (FIG. 4) the piston 60 of which is integralWith axis 49. The jack is fed through hydraulic conduits 61 and 62provided with a distributor 63.

Plate 6 is provided with an annular groove 64 which retains theshouldered end 65 of a rod 66 slideably mounted in the frame of thelathe and which is terminated by the teeth of a rack 67 which engageswith a pinion 68.

Thus, rod 66 can follow the longitudinal movements of the capstanwithout being rotatably driven by the latter.

On the axis of pinion 68 is provided a drum 69 (FIG. 9) carrying theinformation tracks 70 which are used to actuate switches 7l, 71a, 71b,71e, 710?, 71e, 711, and which determine various movements of the lathemembers.

These switches are carried by a support 72 slideable on two rods 73carried by an assembly 74 which pivots about an axis 75 (FIGS. 4 and 9).The pivotable assembly 74 is pulled by a spring 76 and comprises a stop77 abutting against the end of a rod 78. This rod 78 is the rod ofpiston 79 of jack 80 a chamber 81 of which can be fed with pressurizedoil provided by the feeding conduit 61 of jack 59 which controls thelongitudinal positioning of fork 48.

When fork 48 is engaged with roll 47, this means that a hydraulicpressure has built up in chamber 82 .of jack 59 and, consequently, alsoin chamber 81 of jack 80. Piston 79 then pushes back stop 77 and causesassembly 74 t0 pivot in the direction which moves the electric switchessuch as 71 away from tracks 7 0. This movement is nocessary since, asshall be explained hereafter, there exists a control capable ofinterfering to transversely displace the assembly of switches 71 Withrespect to tracks 70, so that if the switches Were to remain againsttracks 70 there would be a serious deterioration risk for these tracks.

A limit switch 84 which is actuated by the end of longitudinal bar 66(FIG. 4) allows of' controlling that the capstan bas reached itsbackward position necessary for its angular indexing.

Moreover, FIG. 4 shows a stop bar 85 which carries stops 86 and therotation of which is controlled by a star 87 integral with said bar andcapable of engaging any one of rolls 47 during the rotating movement ofthe capstan in its return position (cf. FIG. 7).

Note: Stop bar 85 and longitudinal bar 66 are not actually located inthe same plane in the finished machine (FIG. 4), but, in order tosimplify the drawings they have both been shown in the plane .of thesheet of paper in this figure; it is for this reason that the distancebetween the axis stop bar 85 and the capstan axis had to be exaggerated,so that rolls 47 which are carried by plate 6 integral with said capstanseem to describe a circumference which does not reach star 87 whereasactually, as can be seen in FIG. 7, these rolls 47 engage in turn Withthe hollow spaces between the teeth of said star.

Onto stop bar 85 is slideably keyed a cam 88 (FIGS. 4 and 9) which aremaintained stationary in axial position with respect to the frame of thelathe by means of a fork 89 integral with said trame.

Stop bar 85 terminates in a shouldered head 90 engaged in an annulargroove 91 of plate 6, in such a way that said bar moves longitudinallyWith the capstan and can tum only about its own axis when star 87 isdriven by one of rolls 47.

When stop bar 85 is rotating, cam 88 acts upon a pushrod 92 (FIG. 9)which abuts against the end of a lever 93 which is pivotable about anaxis 94 and the other end 95 of which rests against support 72 which ispushed by a spring 72a and onto which are fixed all of the electricswitches such as 71. As a result of this, the rotating movement of thecapstan can determine a change of tracks analysed by these switches.

Fi1ially, th stop bar carries a plate 96 (FIGS. 4 and 5) in theperiphery of which riders such as 97 can be fixed which are capable ofactuating an electric switch serving to control, for instance, thecontinuation of the passing movement from one face of the capstan toanother, in case one or more of the capstan faces should be idle; inother words: to avoid that the capstan is stopped at certain undesiredangular indexing positions.

FIG. 6 is a sectional view of the control box for the longitudinalmovements of the capstan.

The motion is picked up from the spindle 2 of the lathe and transmittedt0 a feed box by means of pulleys 99 and 99a, and a belt 100.

The movement that enters is transmitted to the feed box by means of anendless screw 101 and a toothed wheel 162. It is transmitted bydogclutches 103a to 103 of pinions 104d to 104e to a sprocketwheel 105,106, 107 and 108.

This box which is not a constituent of the present invention may be ofany convenient type. In the example shown it is actuated byelectro-magnets 109g to 109c and comprises an inverting gear system 110,as well as an electro-magnetic clutch 111. In a preferred application,clutch 111 is constituted by a brakeclutch to obtain precisedisplacement stops.

Pinion 108 rotatively drives slide-valve 3 of a hydraulic valve 112,this slide-valve carries at one of its ends an endless screw 113 meshingWith a toothed wheel 114. By means of clutch 115 driven byelectro-magnet 116 in such a way that said clutch meshes when theelectro-magnet is de-energized, toothed wheel 114 drives a helical gear117 which meshes With a screw 118 acting, With respect to pinion 117, asa simple rack.

Screw 118 can only move in the longitudinal direction within the feedbox housing and is connected to capstan 4 by means of a collar device119 which permits the capstan t0 rotate.

Valve 112 is connected to hydraulic conduits a and I) of the hydraulicjack which control the longitudinal movements of the capstan, and is fedby an inlet conduit 1219. It may be of any type known per se whichallows of equillibrating the forces which act upon the two faces etpiston 44 (FIG. 4), or of disequilibnating said forces in one way or theother to determine the advance movement of the capstan in thecorresponding direction.

Thus, the device described and shown in FIG. 6 comprises a rotatingmovement inlet from spindle 2 and an inlet for the motion of translationfrom the longitudinal displacement of the capstan actuated by the jackhoused within said capstan.

These two movements are constantly compared and determine adjustment ofvalve 112, so that the longitudinal movements of the capstan aredirectly dependent from the movement given by the spindle.

The disengagement obtained When electro-magnet 116 is energized opensvalve 112. A supplementarv conduit 121 which opens into chamber 122 ofthe valve confers to the slide-valve a preferential motion towards theright (FIG. 6), and the disengagement permits this motion by determiningthe rapid longitudinal return of capstan 4.

The device further comprises an electro-magnet 123 capable of pushingthe slide of the valve back towards the left, after disengagementobtained by means of electromagnet 116. In this case, one obtains therapid longitudinal advance of the capstan.

At the end of the rapid return of the capstan a stop 124 which iscarried by screw 118 acts upon a system of rods 125 to pnsh back, bymeans of a pivoting lever 126, the armature 127 of electromagnet 123,and to re-equilibrate hydraulic valve 112, thus determining a precisestopping of the rapid return.

What has been described above concerns the operating displacements, aswell as the rapid advance and return of the capstan.

FIGS. 4 and 6 further show elements which serve to obtain precisestoppings of the longitudinal movements of the capstan whcn operating,through stops 86 which are carried by stop bar 85.

A valve 128 which comprises a slide-valve 129 controls the stopping ofthe capstan. Slide-valve 129 is integral with a plate 130 located on thepath of stop 86 which has bcen selected for obtaining the desiredstopping position. Valve 128 is connected, on the one hand, throughconduit a (FIG. 4) with the hydraulic circuit 3 (FIG. 6) of thelongitudinal control of the capstan, and, on the other hand, with oiltank 137. Through a spring 13012 slidevalve 129 is biassed in thedirection of the connection of the valve with the oil tank.

When stop 86 comes into contact with plate 130, slide- Valve 129 isdisplaced towards the left and partially obturates the outlet towardsthe hydraulic oil tank 137 until an equilibrium of the forces actingupon the faces of piston 44 has been obtained, which determines theprecise stopping of the advance movement.

In the drawings all of the hydraulic feeds are diagrammatically shown bypumps 138.

The lathe which has been described hereinabove can, obviously, becompleted by any electric installation deemed necessary for determiningthe operating cycles to be obtained, i.e. the sequency of theoscillating and longitudinal movements of the capstan.

This electric installation comprises, of course, switches 28, 29, 30,42, 71, 71a to 71 83, 84, and 89, which have already been dcscribedabove, as well as switches 133, 134 and 135 (FIG. 2) located in front ofa drum 131 which is integral with stop bar 20, said drum comprisingtracks 132 which are thus scanned by said switches 133 to 135. By way ofexample, and for each one of the angular positions of the stop bar 20which corresponds itself to a given operating station of capstan 4,switches 133 to 135 permit, if desired, to use the oscillating movementof capstan 4 in order to realize a great variety of machining cycles incombination with the main longitudinal displacement of the capstan.

FIG. 4 further shows two limit switches, 141 and 142 which are actuatedby the rod of piston 60 of jack 59, as well as an intermediate switchactuated, as switch 84, by longitudinal bar 66 (FIG. 6), a switch 143actuated by pivotable lever 126 and, finally, in FIG. 8, twolimitswitches 144 and 145 actuated by the rod of piston 50 of jack 49.

I shall now describe an exemplary automatc machining cycle carried outon this lathe. The origin of the cycle is to be found at point A of thediagram in FIG. Il, this point corresponds to the longitudinal positionof the capstan at the greatest distance from the headstock of the lathe.The workpiece-carrying spindle is rotating. The capstan starts byetfecting a rapid approaching movemen't from point A to point B, thenfrorn point B to point C, at a normal operating advance speed whichshall be called hereinafter normal operating advance speed 1/1; frompoint C to point D a movement at slow operating speed l/x; then, frompoint E, a movement at slow operating speed l/y. At this point B oneconfers to the capstan the first phase of an oscillating or angularbalancing movement the amplitude of which is materialized in the diagramby the distance et points E and F, this movement being carried out at anormal operating speed, for instance for the facing of a shoulder. Then,while being left in the angular position it has just reached, thecapstan is subjected to a longitudinal return travel from point F topoint G at normal operating advance speed, e.g, to carry out a finishingoperation on a bore roughly turned during the advance stroke of thecapstan. To this effect, -a double tool is used which comprises a roughcutting tool which operates during the advance travel, and a finishingcutter which operates during the return travel.

At point G the capstan is subjected to the second phase of its angularbalancing movement, in other words it is made to pivot in the opposeddirection from point G to point H- where it resumes its angular indexingreference position; in the example considered, this pivoting movement issupposed to be carried out a high speed. {\t last the capstan is broughtback, by a movement of ax1al translation, from point H to its point ofdeparture A. The actual machining cycle is then finished, but it remainsto index the capstan angularly, operation which is representeddiagrammatically by the rectangular J, K, L, M, I in FIG. 11. Arrow JKsymbolizes the axial movement carried out by fork 48 (FIGS. 4 and 7) inorder t0 engage with the corresponding roll 47; arrow KL symbolizes thepivoting motion of the fork, i.e. the indexing of the capstan at /5turn; arrow LM symbolizes the return movement of the fork and,consequently, its disengagement from the roll, and, finally, arrow MJsymbolizes inverse pivoting motion of the fork when returning to itsinitial position.

It will be noted that during the duration of the machining cycle, fromthe moment when a groove 7 of the plate 6 has been engaged on prism 13,the capstan has been angularly maintained by said member, withoutinterruption, and, consequently, with great precision without anypossibility of clearances being taken up, until completion of its returnto the initial point A.

I shall now describe in detail this automatic machining cycle, withrefcrence to the electric layout in FIGS. 10-1, 10-2.

The manually controlled general interruptor I is closed. The primary oftransformer Tr is fed by two phases of the triphase distributingnetwork, and the secondary delivers a 28 volt tension which is rectifiedand gives, on the one hand, a 24 volt tension to the various controlelectromagnets and, on the other hand, an alternate volt tension fordirect fceding of the trip coils.

Push-button BM1 is pushed clown whereupon the coil of contact C is feedthrough the stop push-button BAI and through the two contacts of themagneto-thermic circuit-breakcrs which are located, respectively, on thefeeding circuit of the spindle motor MB and the advance motor MA whichdrives pump 138 which furnishes the pressurized oil. Energizing of thecoil of contact C causes the tripolar contacts Cl of said contacts to beclosed. The spindle motor and the advance motor start rotating.

The auxiliary contact C3 of contact C closes and ensures the feeding ofthe relay control circuit.

To initiate an automatic cycle push-button B2 is pushed clown. Contact133 which is controlled by the information drum 132 (FIG. 2) is closed.Contact Rb1 is closed since relay RB is energized by contact 83 (FIG. 4)which serves to check the return of the information drum scanningcontacts 69 to their operating position (FIG. 9). Contact Rsl is closedsince relay Rs is energized by limit contact 29 of the stop revolvingjack (FIG. 2), by limit contact 144 of the capstan indexing jack (FIG.8); and by contact R111 since relay Rh is energized by contact 84 whichis closed by the longitudinal bar 66 in the initial longitudinalposition of the capstan.

Thus relay Ra is energized. Contact Ra1 is closed and relay Rd isenergized through this contact Ra1 and the closed contact R11. ContactRal closes, contact Rb2 is closed, and contact 71]), which is controlledby the information drum 69 (FIG. 9) is also closed, so that relay Re isenergized while its contacts Rcl and Rc2 close. This causeselectro-magnet 123 and electro-magnct 116 to become energized.Energizing of electro-magnet 123 (FIG. 3) moves slide-valve 3 towardsthe left in this figure, so that chambcr 46 of the longitudinaldisnlacement jack of the capstan is connected with the hydraulic oiltank by conduit b, the space of slide-valve 3, conduit e, the space ofslide-valve 129 (FIG. 4), and oil tank 137.

Energization of elcctro-magnet 116 (FIG. 6) disengages clutch 115, sothat piston 5 of the jack moves rapidly carrying along the capstan in arapid movement towards headstock 1 (FIG. 1).

The rapid movement of the capstan towards the head. stock 13 convertedinto an operating advance movement,

9 always toWards the headstock, as soon as contact 7112 actuated byinformation drum 69 (FIG. 9) is opened. This opening causes relay Re tobecome de-energized so that contact Rcl is opened, and shuts oI thefeeding of electro-magnet 123 (FIG. 6) so that the hydraulic feed duringthe rapid motion is interrupted while, at the same time, the opening ofcontact RC2 deenergizes electro-magnet 116 so that clutch 115 is broughtto engage. The closing of contact Rc3 leads to e'nergizing ofelectro-magnet 111 by contacts Rb3, RC3, R112 and Rh2. Energizing ofelectro-magnet 111 ensures engagement of. the advance box on thekinematic chain which controls the rotation of the endless screw 113(FIG. 6). Thus the longitudinal displacement of the capstan is carriedout under the effect of the adjustment of the connection of the :chamber46 of the main jack with the hydraulic oil tank through conduit b,slide-valve 3 controlled by its own rotating motion together with therotation of toothed wheel 117 about screw 118 lon gitudinally integralwith the capstan, by conduit e (FIGS. 4 and 6), slide-valve 129 and oiltank 137, whereas the oil under pressure which is delivered by pump 138(FIG. 6) is carried to chamber 45 of the main jack through conduits 120and (1.

This advance is used, for instance, for carrying out a turning ofioper-ation at the speed which has been called hereinabove the normal 1/1speed.

To carry out an -operating advance at slower speed, called low speedl/x, dog-clutches 1t)3a (FIG. 6) are made to engage by energizingelectromagnet 10942 under the effect of the closing of contact 71dactuated by information drum 69 (FIG. 9). Thus, the energization ofelectromagnet 109 produces, solely through the action of the feed box, areduction of the rotating speed of endless screw 113 (FIG. 6), so thatthe longitudinal advance operating speed of the capstan is brought downat the same rate, since nothing else is modified in the remainder of thetransmitting system.

Similiarly, closing et contact 71e actuated by information drum 69 (FIG.9) which is actuated in turn by longitudinal bar 66 (FIG. 4), causeselectro-magnet 109!) to be energized and, hence, engagement etdog-clutches 1630 instead of engagement of dog-clutches 103d Within thefeed box. The operating advance'speed of the capstan is modified andassumes the value called SlOW speed l/y.

When the limit of the operating stroke has been reached stop 86 (FIG.4), which during operation is carried by stop bar 85 ensures closing ofslide-valve 129 when the latter abuts against plate 130 and pushes thesame back towards the left (in FIG. 4), slide-valve 129 acting toobturate the connection with oil tank 137. The operating advancemovement of the capstan is stopped. Despite this hydraulic stop thekinematic chain which controls the rotation of slide-valve 3 (FIG. 6)temporarily continues tu1ning the same. Now, the worm rack 118 integralwith the capstan is stopped and iinmobilizes pinio'ns 117 and 114.Slide-valve 3 which is extended by an endless screw 113 engaged onpinion 114 moves axially over a small distance and causes lever 126 topivot so as to actuate switch 143 which causes electro-magnet 111 to -bede-energized, and thus stops the rotating movement of slide-valve 3.

It is assumed that the work to be done now requires a transversepivoting motion of the capstan with hydraulic adjnstment, e.g. for ashoulderfacing operation on the work-piece which is being machined.

This motion is ensured by energizing electro-magnet 36 (FIG. 2), forreasons which shall be explained hereafter, slide-valve 31 movesdownwardly in FIG. 2, pump 138 delivers oil under pressure into chamber19 of jack 17, while the -oil contained in the other chamber 18 of saidjack returns to oil tank 137 via conduit 136, delivery regulator 41, thechamber of slide-valve 31 and conduit 40. Piston 14 of jack 17 movesdownwardly (FIG. 2) and causes the capstan 4 t pivot about acorresponding angle.

Electromagnet 36 is energized by contact R01 et elay R0 which isenergized by the three contacts Rk1, Rm1, and Rr1. Contact Rkl is closedwhen relay Rk is energized by the closing of contact 143 (FIG. 6).

Contact. Rml is closed because relay Rm is energized by contact 134closed by information drum 131 (FIG. 3).

Contact Rr1 is closed since relay Rr is energized by contact (FIG. 2),and by contacts Rm2 and R221, relay Rll being energized by contact 30(FIG. 2), and by contact R02. When the transverse hydraulicallyregulated rotating advance movement contes to an end, plate 16 (FIG. 2)pushes back stop 22 in function.

The mechanical pressure which is then applied to this stop serves topush back valve 31 by means of lever 33 which is pivotable about axis34, and causes the forces to beequilibrated on both sides of piston 14thus provoking a precise stop of the transverse movement.

The downward displacement of stop bar 20 has actuated switch 42 which,owing to the directions implied by the new position of the capstan,shall permit the cycle to -be continued, in accordance with the settingof the various auxiliary control mechanisms.

In the example considered the setting is as follows:

(1) The pivoted capstan shall be maintained in its resting positionagainst stop 22;

(2) an inversed longitudinal operating advance movement shall beactuated.

Here we have the case of a particular cycle which depends onpreselective information indicated on the perforated tracks 132 of drum131 provided for this use.

Thus, switch 134 has previously established the encrgizing circuit ofrelay Rm the contact Rm1 of which has permitted the capstan to carry outits pivoting movement. On the other hand, contact Rm2 and switch 135have energized relay Rr which serves to momentaneously maintain thecapstan in the pivoted position.

Indeed, it has been noted previously that switch 42 was actuated duringthe stop of the pivoting movement. Relay Tp2 being energized by 42,contact Tp2a normally should have deenergized relay R0 which would havedeenergized electromagnet 36 and thus have caused the inverse pivotingmotion of the capstan. However, this action of Tp2a is being annulled bycontact Rr1 which is closed across the circuit. Thus, Ra remainsenergized and'the capstan remains in its angular position.

The movement which is to follow consists in conferring to the capstanassembly an inverted longitudinal operating advance movement.

Since it is desired to obtain this inverted advance, and since the sameis not obligatory, it is necessary to cause switch 71 to intervene whichhas been provided for this purpose on the longitudinal drum 68. Thisswitch 71c establishes the energizing circuit for relay Re with thefollowing contacts; R1'2 closedRj2 resting, Rk3 closed and Rpl which hasjust been closed by switch 42.

Note 1: Parallel to Re relay Rf is also energized by contact Rpl. Thisrelay is called upon to control the rapid inverted longitudinalmovement, by means of its contact Rf2 on time-delayed relay Tpl. In thepresent case, this action is being annulled by contact Re3 which hasjust been opened.

Note 2: The presence of time-delay relay Tpl is made necessary by thefact that relays Re and Rd are energized simultaneously. Since theaction of the first consists in momentaneously annulling the action ofthe second, it was necessary to delay the action of the first during theswitching period of contacts Re3 and R 2.

Thus, the inverted operating advance is ensured by contacts Re1 and Re2,which simultaneously energize clutch 111 (operating advance), andelectro-magnet 169c (inverting of* the advance).

The inverted advance is pursued until bar 66 acts upon switch (or, ifdesired, until the opening of switch 71c which would cause rapidinverting until switch 140 is actuated).

Switch 140 energizes relay Rj through a circuit established With contactRp4 (Rp being energized by 42, still informed).

At this moment Rj2 de-energizes relay Re the contacts Rel and Re2 ofwhich stop the inverted advance by disengaging 111 and 109c.

Simultaneously Rj4 interrupts the self-excitation of RI. Contact Rrl byleaving its operating position opens the maintaining circuit of R(contact Tp2 being already open since 42 has been informed).

The return of contact R01 to its rest position interrupts feeding ofelectro-magnet 36, which causes the return of the capstan to its initialangular position.

With contact R02 being at rest switch 30, which has been informed by thereturn to the initial position, encr- .gizes relay R11.

Contact R112 is closed and energizes R) through closed circuits Rp1 andRjl, as well as R113 and Rs2 at rest.

Contact Rf2 and Re3 at rest energize the time-delayed relay Tp1 thecontact Tp1a of which energizes electromagnat 116.

This electro-magnet 116 disengages clutch 1115 which permits valve 3(FIG. 6) which is subjected to the hydraulic pressure applied in chamber122, to move towards the right.

This displacement realizes on the one hand obturation of conduit c and,on the other hand, the connection between pressure inlet 121 and conduitb.

The dierential thrusts which are applied at this moment in chambers 45and 46 on both sides of piston 44 cause the rapid longitudinaldisplacement of the capstan towards its initial position opposed to theheadstock.

When the head 124 (FIG. 6) of screw 118, which is longitudinally drivenby the capstan, knocks against plate 125 it brings slide-valve 3 back tothe position wherein it causes the return of the capstan to be stopped.

When the capstan resumes its initial position, bar 66 actuates switch 84the closing of which leads to electrovalve 63 being energized so thatchamber 82 of jack 59 (FIG. 4) is fed while fork 48 engages With roll 4710- cated in front thereof, switch 142 being actuated by the same jackwhich leads to electro-valve 58 (FIG. 8) being energized and,consequently, to feeding of chamber 57 of jack 50 the piston 51 of whichcauses crank pin 55 and shaft 49 to pivot in the direction of arrows f2,fork 48 (FIG. 7) pivots about the same angle, and the capstan pivots /5turn in the direction of arrow il. Simultaneously, star 87 (FIGS. 4 and7) also pivots Ms turn and permits stop bar 85 to revolve while piston26 (FIG. 2) withdraws (towards the left) under the effect of thepressure of the oil fed to jack 27 by conduit c temporarily fed byelectro-valve 58 (FIG. 8). v

Switch 145 (FIG. 8) opens when piston 51 has reached the limit of itsangular capstan indexing stroke, which de-energizes electro-valve 63(return movement et piston 60, and disengagement of fork 48 from roll47). Switch 141 interrupts electrovalve 58, piston 51 resumes itsposition shown in FIG. 8, While piston 26 resumes its position shown inFIG. 2 and causes stop bar 20 to revolve /5 turn, by means of catches 24and 24a and ratchet 23 which is integral With said bar.

The cycle is finished. With respect to the beginning of this cycle mostof the members assume the same positions, but capstan 4 and stop bars 20(FIG. 2) and 85 (FIG. 4) have been indexed /s turn, another notch 7(FIG. 2) of plate 6 integral With the capstan has come to engage on theangular advance prism 13 at the return of the capstan to its initiallongitudinal position, the coupling of switches 133, 134, 135 (FIG. 2)may have been modified, and the position of switches su-ch as 71 (FIG.9) used for the scanning of the tracks 70 of. programming drum. 69 mayhave been modified under the action of the 12 pivoting motion of cam 88rotatably connected With stop bar 85.

The automatic repetition of a machining cycle is initiated byenergizing, relay Ra (FIG. 101) when switch 71a (cf. also FIG. 9) isbeing closed instead of being initiated by means of push-button B2.

Furthermore, in case not all of the faces et the capstan should be usedit is possible to cause directly one or more renewals of the indexing,controlled by the presence of riders 97 (FIG. 5) which actuate switch98.

The longitudinal situation of the capstan is controlled, on the side ofthe loose head, through switch 84 (FIG. 4) on its path, through switch140 (same figure), and on the side of the head-stock through switch 143(FIG. 6), all of which can be seen in the general electric layout.

As regards control of slide 10 (FIG. 2) for the angular advancemovements of the capstan, the following features may be taken intoconsideration:

(a) Selection of special cycles for switch 134 and information drum 132(FIG. 2);

(b) Upper position under control of switch 30 (also in FIG. 2);

(c) Downward movement actuation under control of electro-magnet 36;

(d) Lower stroke limit under control of switch 42 With timelag throughrelay Tp2;

(e) Maintaining special cycles in the low position under control ofswitch and information drum 132.

The origin of the indexing cycle is controlled by switches 29 (FIG. 2)and 144 (FIG. 8).

Finally, relay Rw controls an indexing, memory capable of avoiding anyundesirable capstan indexing repetition.

What I claim is:

1. A mol-holding capstan mounted so as to be capable of being subjectedto a motion of translation in a parallel direction to the axis of thework-piece carrying spindle of the lathe and rotating movements about anaxis parallel to said spindle in order to be able, on the one hand, toassume different angular indexing positions for which the tools carriedby its faces successively present themselves at the operating station,and, on the other hand, to carry out an oscillating or angular balancingmovement originating from each of said angular indexing positions inorder to confer to the tools a transverse motion, said lathe beingcharacterized by the fact that the member which maintains the capstan ineach of the angular indexing positions thereof is movable on the frameof the lathe, between a stationarv stop which determines said positionand an end position which determines the position of maximum amplitudeof the angular balancng movement of the capstan ensured by the movementof said maintaining member which permanently determines the angularposition of the capstan under the action of convenient control means.

2. A lathe according to claim 1, characterized by the fact that themember which permanently determines the angular position of the capstanis constituted by a prismatic guide capable of receiving any one of aseries of radial grooves With parallel sides provided at the peripheryof a plate which is integral With the capstan, said guide beingconnected to a slide which is movable in an orthogonal direction Withrespect to the axis of the capstan and subjected to the action of theabovementioned control means.

3. A lathe according to claim 2, characterized by the fact that theslide which carries the guide maintaining the angular position of thecapstan is connected to one of the elements of a hydraulic jack which isstopped when equilibrated under the control of a hydraulic slide-valvecontrolled by a micrometric stop actuated by said slide.

4. A lathe according to claim 2, characterized by the fact that thelocation and length of the guide are such that the plate in tegral Withthe capstan is disengaged from said guide when the capstan has reachedat least one of the two end positions of its motion of translation.

5. A lathe according to claim 2, characterized by the fact that theconnection between the prismatic guide and the slide is constituted byhinge about an axis parallel to that of the capstan.

6. A lathe according to claim 3, characterized by the fact that themicrometric stop is carried by a stop bar which comprises as many ofthese micrometric stops as the capstan has too1 receiving faces, saidbar being mounted so as to be capable of being slightly displaced in theaxial direction by the slide and of actuating the hydraulic slide-valveto carry the same to its position of equilibrium, as well as in thecircumferential direction under the action of an indexing device capableof carrying each stop selectively onto the path of said slide.

7. A lathe according to claim 3, characterized by the fact that thehydraulic circuit of the jack comprises an adjustable throttle Withvariable cross-section capable of regulating the speed of the angularbalancing movement of the capstan.

8. A lathe according to claim 1, chara-cterized by the fact that thelathe is connected to a movable member of a hydraulic jack Whichcontrols the longitudinal displacement of said capstan, the stopping ofsaid jack being caused by its being equilibrated under the control of ahydraulic slide-valve controlled by convenient auxiliary means.

References Cited by the Examiner UNITED STATES PATENTS 2,148,348 2/1939Groene et al 8221 X 2,635,325 4/1953 Walder 29-42 ANDREW R. IUHASZ,Primary Examiner.

LEONIDAS VLACHOS, Examiner.

1. A TOOL-HOLDING CAPSTAN MOUNTED SO AS TO BE CAPABLE OF BEING SUBJECTEDTO A MOTION OF TRANSLATION IN A PARALLEL DIRECTION TO THE AXIS OF THEWORK-PIECE CARRYING SPINDLE OF THE LATHE AND ROTATING MOVEMENTS ABOUT ANAXIS PARALLEL TO SAID SPINDLE IN ORDER TO BE ABLE, ON THE ONE HAND, TOASSUME DIFFERENT ANGULAR INDEXING POSITIONS FOR WHICH THE TOOLS CARRIEDBY ITS FACES SUCCESSIVELY PRESENT THEMSELVES AT THE OPERATING STATION,AND, ON THE OTHER HAND, TO CARRY OUT AN OSCILLATING OR ANGULAR BALANCINGMOVEMENT ORIGINATING FROM EACH OF SAID ANGULAR INDEXING POSITIONS INORDER TO CONFER TO THE TOOLS A TRANSVERSE MOTION, SAID LATHE BEINGCHARACTERIZED BY THE FACT THAT THE MEMBER WHICH MAINTAINS THE CAPSTAN INEACH OF THE ANGULAR INDEXING POSITIONS THEREOF IS MOVALE ON THE FRAME OFTHE LATHE, BETWEEN A STATIONARY STOP WHICH DETERMINES SAID POSITION ANDAN END POSITION WHICH DETERMINES THE POSITION OF MAXIMUM AMPLITUDE OFTHE ANGULAR BALANCING MOVEMENT OF THE CAPSTAN ENSURED BY THE MOVEMENT OFSAID MAINTAINING MEMBER WHICH PERMANENTLY DETERMINES THE ANGULARPOSITION OF THE CAPSTAN UNDER THE ACTION OF CONVENIENT CONTROL MEANS.